Pitman connection.



Patented Sept. 24, 190|.

E. A. JHNS-TON.

(Application filed Decf22, 1900.)

(No Model.)

UNTTED STATES PATENT OFFICE.

EDWARD A. JOHNSTON, OF CHICAGO, ILLINOIS.

PITMAN CONNECTION.

SPECIFICATION forming part of Letters Patent N o. 683,049, datedSeptember 24, 1901.

Application tiled December 2.2, 1900l Serial No. 40,751. (No model.)

To all whom t may concern,.-

Be it known that I, EDWARD A. JOHNSTON, a citizen of the United States,residing at Chicago, county of Cook, and State of Illinois, haveinvented certain new and useful Improvements in Pitman Connections; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to improvements in pitman connections, and pertainsmore particularly to joints for use iu connection with the knife headsof mowing machines, although it is adapted for use in all analogousrelations where a flexible connection between moving parts is desired.

The object of my invention is to provide a ball-and-socket connectionbetween the pitman and the reciprocating part wherein the connectionbetween the ball-bearing and the respective sockets is maintaineduniform by spring-pressure and all wear between the parts isautomatically compensated for.

My invention is illustrated in the accompanying drawings, in which-Figure l is a plan view of my improved pitman connection as applied tothe knifehead of a mowing-machine. Fig. 2 is a side elevation thereof.Fig. 3 is a longitudinal section through my improved connection, showingthe parts in operative relation. Fig. It is a plan view illustrating thespoons in open position. Fig. 5 is an enlarged sectional elevationshowing the manner of connecting the adjusting means with the respectivespoons. Fig. 6 is a detail of the adjustingnut. Fig. 7 is a fragmentaryview in section of the respective spoons. Fig. S is a side ele# vationof the movable spoon.

Referring to the drawings, A represent the pitman of a mowing-machine,to which is firmly secured the spoon a by means of integral straps lyingalong the respective sides of the pitman. Pivoted in suitable earsprojecting from the spoon a/ is a second coperating spoon ce, whosesocket a4 lies adjacent to the corresponding socket 0.5 of the spoon a.The spoon a' has'a lateral perforation to receive a bolt C, whosepolygonal head c2 tits a bearing in a corresponding socket a7. The spoona has an enlarged orifice as extending through it, which bears on itsinner wall two projecting cams d10, each of which extends part Wayaround said wall, leaving a space between their contiguous ends.. Theupper rim of this orifice has two diametrically opposite notches a9, thepurpose of which will be described later. The upper end of the bolt C isscrew-threaded to receive a correspond- 6o ingly-threaded nut E, whichhas the custom- Y ary wings or finger-pieces a3 and is provided with twodepending lugs or ears e, terminating in inelines or cam-surfacescorresponding to the cams aw. 6 5

Surrounding the bolt and attached at one end to the spoon a and at theother to the nut E is a spiral spring c, which is normally under tensionand tends to force the nut upon the screw-threads of the bolt toward thehead 7o thereof. Spoon a has two lugs 0.6, which prevent the spoonsbeing brought too close toA gether, thereby causing' the joint to bind.The pitch of the threads on the bolt C corres sponds to the inclinationof the cams 0.10, so that as the spring c turns the nut E the latter isforced upon the threads of the bolt toward the head and the lugs e aremoved upon the cam am, thereby moving the spoon a toward the spoon d.

The parts when properly assembled bear the specific relation to eachother illustrated in Fig. 3, wherein the nut E has been turned so thatits cam-lugs e engage and ride upon the corresponding cams am on thespoon a, thereby drawing the spoon a. toward the spoon a and causing therespective sockets a4 and a5 to embrace the ball-bearing b' on thebracket b of the knife-headB. The pressure between parts of theball-and-socket joint is just suf- 9o ficient to insure a good bearing,neither too tight nor too loose, and the degree of this pressure mayreadily be regulated by adjusting the tension of the spring. To separatethe parts, it is only necessary to turn the thumb-nut until its earscomeopposite the notches ai in the rim of the spoon a. In this position thecams e on the nut are disengaged from the corresponding cams d10 on thespoon and the pivoted spoon is forced away from the roo fixed spoon bythe spring, so that the ears e3 engage the socket 0.9 and the parts areheld locked in open position.

This construction is simple and effective as compared With thoseformerly in use. It is not necessary that the spring be a heavy one tosecure the parts in locked position, as the vibrations of the pitmanwill tend only to force the cams of the nut E higher up the inclines ofthe cams on the spoon. Furthermore, the device is much to be preferredto the old constructions where unskilful workmen are employed in that itis self-adjusting and once the degree of tension is determined it is notnecessary to readj ust the parts after each removal of the knife-head.

Having thus described my invention, what I claim is- 1. A pitmanconnection, comprising coperating spoons, a bolt passing through saidspoons, a nut on said bolt, cooperating cams on said nut and one of saidspoons, a spring attached to said nut and the other of said spoons,whereby said cams are caused to engage, and said spoons are forced intooperative position.

2. A pitman connection, comprising coperating spoons, a bolt passingthrough said spoons, a nut threaded on said bolt, coperating cams onsaid nut and one of said spoons, a spiral spring attached to said nutand the other sp'oon, whereby said nut is caused to turn on the bolt andsaid coperating cams are made to engage to force the spoonsintooperative relation. Y

3. A pitman connection, comprising cop erating spoons, a bolt passingthrough said spoons, a nut threaded on said bolt, camlugs on said nutWorking in a ianged orifice in one of said spoons, cams on the walls ofsaid orifice, a spiral spring attached to said nut and the other spoon,whereby said cams are engaged to close the spoons, and means fordisengaging said cams.

4. A pitman connection, comprising a fixed and a movable spoon, a boltpassing throughh

